1. Field of the Invention
The present invention relates to a process for developing a light-sensitive photographic material for photographic printing plates useful in the graphic arts, and more particularly, relates to a process for developing a litho-type light-sensitive material without the formation of aerial fog which occurs when the light-sensitive material on transfer from a developing solution comes into contact with air.
2. Description of the Prior Art
In litho-type silver halide light-sensitive materials which are used for making photographic printing plates useful in the graphic arts, lithographic films which are used for converting continuous tone images of the originals to be printed into dot images, whereby the density variation of the continuous tone images is converted into area variations of dot images, and lithographic line films which are used for the originals to be printed and having line images are known.
These litho-type light-sensitive materials are generally developed with a so-called infectious developing solution (hereinafter, described as "lithographic development") in order to obtain dot or line images having higher contrast and higher density.
Examples of development processes are tray processings which are carried out by manually developing the exposed photographic materials in plate-like vessels filled with the developing solution and automatic machine developing processings which are carried out using automatic developing machines as disclosed in U.S. Pat. Nos. 3,025,779, 3,078,024, 3,122,086, 3,149,551, 3,156,173, 3,224,356 and 3,573,914.
In the developing processings, fog occurs because photographic materials are contacted with air during or after the processings or when they are transported into the following step (e.g., fixing step).
This type of fog is called "aerial fog," and particularly aerial fog often occurs in automatic machine processings because photographic materials ae contacted with air for several seconds to several tens of seconds when they are transported by means of the crossover rolls in the apparatus.
If aerial fog occurs, the minimum density of the dot or line images is increased, and effective density of the images (the difference between the maximum density and the minimum density) is reduced, and, as a result, image sharpness, tone reproducibility and resolving power are reduced. Therefore, desired photographic printing plates cannot be obtained when this occurs. Particularly, the image contrast is reduced and the dot quality is deteriorated when this happens and the exposure time for printing images from photographic plates to printing plates is longer.